Spark-Plug And Thermal Degree - IAME REEDSTER 125cc Assembly Instructions & User Manual

3.12 SPARK PLUG AND THERMAL DEGREE
The engine is supplied with a standard NGK BR10EG, which represents a good
compromise between the needs of a good break-in and the racing needs in normal
conditions.
Use of different spark plugs is possible and, as a general information, we are
attaching a correspondence list among spare plugs of other brands, based on
thermal degree which represents the capacity of the spark plug to dissipate the
internal heat.
The colour of the various parts of the spark plug more exposed to the combustion
flames gives a good indication on the adequacy of the thermal degree and on the
carburetion. It is necessary though to understand which of the two parameters has to
be changed and only the experience tells how to identify the most proper thermal
degree of a spark plug as lean or rich mixtures can generate the same final look
which can also be achieved with a hot or cold spark plug.
See table:
An excessive warm
symptoms, listed aside.
ATTENTION:
Always use a warmer than standard spark plug
with cold or rainy climate..
A correct thermal degree shows:
An excessively cold
symptoms, listed aside.
ATTENTION:
Always use a colder than standard spark plug
with hot climates.
BOSCH
WO8CS
WO7CS
WO6CS
spark plug shows
spark plug shows
COMPARISON TABLE BASED ON
THE THERMAL DEGREE
the Extremely clear
calcification of the electrodes and of the internal
insulation.
Irregularities in the ignition, pre-ignition and
detonation with tendency to perforate the top of
the piston.
Note: some of these symptoms can be
achieved with lean mixtures.
Colour of the insulator end from yellow grey to
dark brown for mixtures respectively lean or rich.
the Insulator end and electrodes covered with black
shady soot.
Ignition difficulties.
Note: a wet or oily electrode could also mean
an excessively rich mixture.
HOT
NGK
BR9EG
BR10EG
BR11EG
COLD
33
colour, porous look
CHAMPION
N54R
N52R
MAN-051 ING
and